How to remove "missing script files" warnings in add-on prefs?
I had the same problem in Blender 2.83.
I suggest that you load the Blender Add-on factory settings by going to the &quot;Edit&quot; menu, Select the &quot;gear&quot; icon to get to &quot;Preferences...&quot; and after that, click on the lower left corner button besides &quot;Save Preferences*&quot; (it shows 3 horizontal lines through it).
Then, by re-enabling the Add-ons one by one, you'll easily spot the culprit for the missing scripts.
Usually, an updated version might have been already published if you do a search for the defective Add-on.
In the case of the Blenderkit being the one giving you problems, go to this answer provided by SHA:
https://blenderartists.org/t/blender-2-8-blender-kit-addon-install-error/1173445/12?u=pierregagne98
Hope that helps!